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    <title>iirlp</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : April 1993</div>
    <p>
      <b>iirlp</b> -  Lp IIR filter optimization</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>[cost,grad,ind]=iirlp(x,ind,p,[flag],lambda,omega,ad,wa,td,wt)  </tt>
      </dd>
    </dl>
    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>x</b>
        </tt>: 1X2 vector of the module and argument of the poles and the zeros of the filters</li>
      <li>
        <tt>
          <b>flag</b>
        </tt>: string : <tt>
          <b>'a'</b>
        </tt>  for amplitude, 'gd' for group delay; default case for amplitude and group delay.</li>
      <li>
        <tt>
          <b>omega</b>
        </tt>: frequencies where the filter specifications are given</li>
      <li>
        <tt>
          <b>wa,wt</b>
        </tt>: weighting functions for the amplitude and the group delay</li>
      <li>
        <tt>
          <b>lambda</b>
        </tt>: weighting (with <tt>
          <b>1-lambda</b>
        </tt>) of the costs (<tt>
          <b>'a'</b>
        </tt> and <tt>
          <b>'gd'</b>
        </tt> for getting the global cost.</li>
      <li>
        <tt>
          <b>ad, td</b>
        </tt>: desired amplitude and group delay</li>
      <li>
        <tt>
          <b>cost, grad</b>
        </tt>: criterium and gradient values</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    optimization of IIR filters for the Lp criterium for the
    amplitude and/or the group delay. (Rabiner &amp; Gold pp270-273).</p>
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